Dual-tip pen



FIG. 1 is a lower front right perspective view of a dual-tip pen showing my new design;

FIG. 2 is a left side elevation view of the dual-tip pen shown in FIG. 1, with a right side elevation view being a mirror image thereof;

FIG. 3 is an enlarged top plan view of the dual-tip pen shown in FIG. 1, with a bottom plan view being a mirror image thereof;

FIG. 4 is a front elevation view thereof; and,

FIG. 5 is a rear elevation view thereof. 

The ornamental design for a dual-tip pen, as shown and described. 